Method of assembling a contrast enhanced display

Abstract

A transparent face plate for a bright display device, such as an airborne cathode ray indicator often viewed under high ambient light intensities, is bonded directly to the viewing face of the display device by a transparent bonding material dyed to provide an optical filter whose transmission characteristics, determined in part by the thickness of the colored bonding agent, are generally matched to the spectrum emitted by the phosphor within the cathode ray tube so as to provide an optimally contrast enhanced display. A unique assembly method and gasket arrangement are used to determine precisely the spacing between the face plate and the indicator viewing face and, therefore, the filter thickness, and to form a temporarily sealed cavity into which the colored or dyed bonding agent is injected and then polymerized.

What is claimed is: 
     
       1. A method for forming a filter-face plate combination on the viewing face of a bright display device incorporating the steps of: supporting said bright display device with said viewing face upward,   placing an elastomer gasket on the periphery of said bright display device viewing face, said gasket having an inner annular lip, one side thereof being adapted to contact said viewing face generally at the periphery thereof,   placing a transparent face plate on the opposite side of said annular gasket lip,   applying pressure to said face plate generally at the periphery thereof thereby to form a cavity defined by said viewing face, said face plate, and the inner surface of said gasket lip, except for a generally radial filler hole extending through said gasket and communicating with said cavity,   reorienting said bright display device so that said radial filler hole is substantially vertical,   filling said cavity through said radial filler hole with a curable polymer material which includes colorants to provide the desired optical filter characteristics while avoiding formation of bubbles,   curing said polymer material,   removing said pressure from said face plate, and   removing said elastomer gasket from said bright display device.   
     
     
       2. The method as described in claim 1 wherein the step of filling said cavity includes: heating a selectively colored, curable polymer material to produce a desired viscosity of said polymer material at a predetermined temperature.   filling a syringe device with said heated polymer material and removing any gas therefrom,   inserting said syringe device into said cavity through said radial filler hole so that the output thereof is adjacent the lower portion of said cavity,   operating said syringe device to extrude the heated polymer material into said cavity and withdrawing said syringe device while maintaining said output below the surface of the extruded polymer material, thereby minimizing formation of bubbles.   
     
     
       3. The method as described in claim 2 further including the step of preheating said bright display device simultaneously to substantially the same predetermined temperature as said heated polymer material. 
     
     
       4. The method as described in claim 3 wherein the step of filling said cavity follows a preliminary step of introducing at least a first light absorbing dye material characterized by a first optical wavelength pass band into said curable heated polymer material substantially at said predetermined temperature. 
     
     
       5. The method as described in claim 4 wherein the step of filling said cavity follows the preliminary steps of: introducing said first and a second light absorbing dye material characterized by a second optical transmittance characteristic into said curable heated polymer material substantially at said predetermined temperature to produce a colored, thermally curable polymer material in liquid form, and   stirring said colored, thermally curable polymer material for thoroughly and uniformly mixing said dye materials therein.   
     
     
       6. The method as described in claim 5 in which the step of applying pressure to said transparent face plate generally at the periphery thereof includes moving a circular pressure plate into contact with said face plate periphery and uniformly increasing said pressure to a predetermined level thereby to define the thickness of said cavity and the resultant optical filter. 
     
     
       7. The method as described in claim 6 including the preliminary step prior to placing said elastomer gasket in the periphery of said display device viewing face of applying a thin layer of mold releasing material to the surfaces of said elastomer gasket contacted by said polymer material. 
     
     
       8. The method as described in claim 1 including the final step of applying within the annular indentation formed in the periphery of said filter by said gasket lip upon removal thereof with a polymerizable flexible material and subsequently curing the latter material.